A lithium battery internally develops a solid electrolyte interface (SEI) passivation layer at one or more of the battery's electrode surfaces during the battery's initial charging cycles. The SEI passivation layer forms when the battery's electrolyte/salt system decomposes on the surface of the battery's electrodes. Once formed, the SEI passivation layer protects the battery's electrode active materials from further reactions with the battery's electrolyte components.